The present invention generally relates to apparatus and method for extracting cataract tissue and more particularly is directed to combined use of vibrational and laser energy to effect cataract removal.
An eye generally includes an anterior chamber and a posterior chamber separated by a lens contained in a lens capsule. The lens functions to focus incoming light onto a retina disposed on a rear wall of the posterior chamber.
Cataracts cause the lens of an eye to become clouded, which interferes with proper transmission and focusing of light on the retina. A common practice to alleviate this condition is by surgically removing the cataractic lens and replacing it with an artificial intraocular lens.
Early lens removal was effected through manual extraction which required a wound of about 12 mm in length. This large opening can result in corneal or sclera tissue damage.
Externally applied laser radiation has been used to soften a cataract lens before manual extraction therefor. See U.S. Pat. Nos. 4,825,865, 5,057,098, 5,112,339, 5,139,504 and 5,403,307. Such manual extraction requires large entry wounds as hereinabove noted.
Phacoemulsification, on the other hand, enables the removal of a cataractic lens through a much smaller incision, for example between about 2.5 to about 4 mm. In this procedure, a needle is inserted through the incision into a lens capsule and the needle is ultrasonically vibrated to mechanically emulsify the lens. Once fragmented, or emulsified, the lens material is aspirated through a lumen through the phacoemulsification needle.
While emulsifying the lens and aspirating lens fragments, a simultaneous flow of irrigation fluid into the lens capsule is provided around the needle through an annulus established by a sleeve concentrically disposed over the needle. This flow of liquid into the eye is necessary to prevent collapse of the anterior chamber of the eye during aspiration. In addition, the irrigation fluid cools the needle in order to prevent any thermal damage of the corneal or scleral tissue. While the sleeve surrounding a phacoemulsification needle provides the important function of establishing an annulus for introducing irrigation fluid into the lens capsule and also enlarges the overall diameter of the sleeve needle for which an incision must be made.
In addition, when irrigation fluid is introduced proximate the emulsifying needle tip, the immediate area in front of the needle is roiled. This occurs because of the counter-current flow of fluid being aspirated by the needle itself and the irrigation fluid being introduced over the surface of the needle. Needle vibration causes a cloud of debris which is roiled by the incoming infusion fluid which lessons the physicians visual acuity of the end of the needle which can slow the procedure.
The present invention provides for the combined use of laser and vibrational energy to remove cataractic lens tissue and overcomes the drawbacks of a sleeved phacoemulsification needle.
Apparatus in accordance with the present invention for the removal of lens tissue generally includes a first handpiece including a laser emitting probe sized for insertion into a lens capsule and radiating lens tissue therein. In addition, the laser emitting probe includes a lumen for introducing an irrigation fluid into the lens capsule.
In combination therewith, a second handpiece is provided which includes a vibrated needle for insertion into the lens capsule and emulsifying lens tissue that has been softened, or fractured, by the laser radiation. The vibrated needle includes a lumen therethrough for aspiration of the emulsified lens tissue and irrigation fluid.
A control console is provided and interconnected with both first and second handpieces for controlling irrigation and aspiration rates and enabling simultaneous sequential operation of the laser emitting probe and the vibrated needle. In this manner, particularly hard or lens portions, that are resistant to emulsification, may be preconditioned for emulsification by laser radiation. The softening of lens tissue by laser is well known as set forth in the hereinabove referenced U.S. Patents.
Because irrigation fluid is not simultaneously introduced proximate the vibrating needle, as is the case in prior art devices, no disturbance or churning of fluid occur which may provide for a xe2x80x9cmilky cloudxe2x80x9d at the end of the needle which can tend to lessen visual acuity, which in turn, may interfere with the accuracy of the phacoemulsification by a physician.
Preferably the second handpiece includes a transducer for driving the vibrating needle at ultrasonic frequencies and the laser emitting probe comprises fiber optics with a irrigation lumen therethrough.
A method in accordance with the present invention for removing lens tissue from a lens capsule generally includes the steps of inserting a laser emitting probe having an irrigation lumen into the lens capsule along with a vibratable needle having an aspiration lumen.
Irrigation fluid is introduced into the lens capsule and the lens is softened or fractured by exposure to laser energy from the laser emitting probe.
The needle is vibrated to emulsify the lens tissue which is thereafter aspirated along with the irrigation fluid through an aspiration lumen in the vibratable needle.
The lens tissue may be exposed to laser radiation and emulsified simultaneously or the laser exposure may be intermittent and in a sequential manner. That is, the tissue may first be repeatedly exposed to laser radiation and thereafter emulsified.